This invention relates to jacking apparatus and more particularly to a pump-motor set having apparatus for separating the motor from the pump.
In a nuclear reactor power plant the nuclear reactor generates heat which is transferred by the reactor coolant to a location remote from the nuclear reactor for the generation of steam and electricity in a conventional manner. In order to circulate the reactor coolant through the system, reactor coolant pumps are located in the reactor coolant circulatory system for pumping the reactor coolant through the system. Typically these reactor coolant pumps comprise a vertical pump with an electric motor vertically mounted on the pump by means of a cylindrical or conical structure known as a motor stand. The electric motor's rotatable drive shaft is connected to the pump's rotatable shaft through a coupling device. In this manner, the rotation of the motor's rotatable drive shaft causes the pump's rotatable shaft to rotate which causes the pump to circulate the reactor coolant through the reactor system in a manner well known to those skilled in the art. One such reactor coolant pump is described in copending application Ser. No. 730,056 filed Oct. 6, 1976 entitled "Vertical Pump With Free Floating Check Valve" by M. Lindsay and assigned to the assignee of the present invention.
Occasionally it is necessary to repair or replace certain parts of the pump such as the pump seals. In the prior art when such repair or replacement was necessary the motor and pump were deactivated and the motor was disconnected from the pump at the coupling interface between the motor's rotatable drive shaft and the pump's rotatable shaft and at the interface between the motor housing and motor stand. Once the motor and pump were disconnected, an overhead crane would then vertically remove the motor thus exposing the top of the pump shaft. At this point, working personnel utilizing common lifting devices such as hoists and cranes would then disassemble and remove the necessary pump parts to enable replacement or repair of the particular part.
There are several problems associated with this prior art procedure for repairing the pump. For example, when it is desired to reconnect the motor to the pump, it is necessary to utilize a very time consuming procedure of realigning the motor drive shaft with the pump shaft to insure proper pump operation. This problem is particularly acute when the pump is utilized in an electric power plant such as a nuclear power plant because the slow process of realigning the motor and pump shafts may result in expensive down time of the power plant and increased maintenance costs. In addition, when the motor is removed from the pump, a large storage area is needed for the motor while the repair is performed. This storage problem is further accentuated in a nuclear reactor power plant because the nuclear reactor and reactor coolant pumps are located in a containment vessel where a provision for storage space can be quite costly. Furthermore, in a nuclear power plant an overhead polar crane is normally utilized to lift and transport the motor. These overhead polar cranes are generally quite slow which results not only in further time delays related to the pump, but also in other time delays since the crane cannot be utilized for other purposes while engaged in the pump repair operation.
One arrangement known in the prior art for eliminating the removal of the motor from the pump consists of building the motor-pump set with a shaft spacer known as a spool located between and attached to the motor drive shaft and pump shaft. When repair of the pump is needed, the motor housing remains attached to the motor stand while the shaft spacer is unbolted from the motor drive shaft and pump shaft. Once unbolted, the shaft spacer can be horizontally removed from between the motor drive shaft and pump shaft thereby providing access to the pump components. In addition, this spool arrangement eliminates the need for realignment of the motor drive shaft with the pump shaft. While the spool arrangement does provide one mechanism for accessing the pump components, there exist situations in which either the spool is not used or additional space is required. Therefore, it is desirable to have an arrangement whereby the motor may be separated from the pump by a satisfactory distance without requiring the use of a crane or without requiring realignment of the motor drive shaft and pump shaft.